Anti-stalling motor fuel composition



United States Patent cc,

3,192,021 ANTI-STALLING MOTOR FUEL COMPOSITION George W. 'Eckert, Wappingers Falls, N.Y., assignor to Texaco Inc., New York, N.Y., a corporation of Delaware No Drawing. Filed June 15, 1962, Ser. No. 202,698 7 Claims. (Cl. 44-63) This invention relates to a motor fuel composition for internal combustion engines having outstanding anti-icing, anti-stalling properties. This improvement in the motor fuel is based on the effect of an additive comprising an alkyl pyridinium halide.

It is well known that spark ignited internal combustion engines employing highly volatile winter grade motor fuels are prone to stalling during engine start-up periods. This problem is generally experienced under atmospheric conditions of high humidity and relatively low temperatures, i.e., humidities above about 70% and temperatures in the range of about 30 to 60 F. Engine stalling under these conditions has been attributed to the blocking of the air passage that exists between the carburetor throat and throttle blade during engine idling by the deposition of ice on the internal metal parts of the carburetor. The ice is formed from the water vapor present in the air drawn into the carburetor. This water vapor is condensed and solidified due to the refrigerating eifect pro duced by the vaporization of the motor fuel in the carburetor.

The stalling problem noted above isencountered with the use of a winter grade motor fuel containing a high proportion of volatile hydrocarbons in the gasoline boiling range. -The volatility of these fuels is expressed as the Reid vapor pressure. Fuels having a Reid vapor pressure above about 9 and up to about 13.5 are particularly prone to engine stalling due to ice formation under cool, humid atmospheric'conditions.

A motor fuel composition has now been discovered which has substantially improved anti-icing, anti-stalling properties brought about by the addition of an alkyl pyridinium halide.

In accordance with this invention, there is provided a motor fuel consisting of a mixture of hydrocarbons in the gasoline boiling range containing an effective antiicing, anti-stalling amount from about 0.001 to 0.1 weight percent of an alkyl pyridinium halide having the formula:

in which R is an alkyl radical having from 6 to 28 carbon atoms and X is a halogen atom.

The alkyl pyridinium halides of the invention are quaternary pyridinium salts and are solids at room temperature. They can be prepared by reacting pyridine with an alkyl halide preferably in a highly polar solvent, such as acetone or nitrobenzene. The alkyl pyridinium halides are preferably dissolved in a solvent, specifically, an alcohol, such as ethyl or methyl alcohol, to obtain better and faster solution in gasoline. An alcohol concentration less than 0.25 percent by volume basis the gasoline can be used economically. The alcohols in this amount do not improve resistance to carburetor icing of a gasoline.

The reason why the alkyl pyridinium halides of the invention function as anti-icing, anti-stalling additives 3,192,021 Patented June 29, 1965 is not fully understood. It is postulated that a molecularly thin layer of the alkyl pyridinium halide adheres to or plates on the internal metal surfaces of the carburetor and functions to prevent the build-up of ice on the critical areas.

The anti-icing additive for the instant motor fuel composition is an alkyl pyridinium halide having the formula:

in which R is an alkyl radical having from 6 to 28 carbon atoms and X is a halogen atom. Generally, alk y1 pyridinium halides in which the alkyl radical contains from 10 to 18 carbon atoms, are preferred. The halogen'substituent can be chlorine, bromine or iodine with the preferred species being chlorine and bromine. Typical effective alkyl pyridinium halides include cetyl pyridinium bromide, cetyl pyridinium chloride, cetyl pyridinium iodide, lauryl pyridinium chloride, lauryl pyridinium bromide, lauryl pyridinium iodide, hexyl pyridinium chloride, hexyl pyridinium bromide, decyl pyridinium chloride, octodecyl pyridinium chloride and bromide and the like.

The alkyl pyridinium halides are effective as anti-stalling, anti-icing agents in concentrations of 0.001 to 0.1 weight percent of the motor fuel composition. Higher concentrations'can be employedbut there is nov significant advantage. Generally, lower concentrations of the alkyl pyridinium halide generally within the range of 0.001 to 0.02 weight percent are quite effective and are preferred for this invention. In formulating motor fuel compositions, it is customary to add the additive in pounds per thousand barrels (11th.). 8 p.t.b.' of the anti-icing additive in the motor fuel is equivalent to a concentration of about 0.003 weight percent.

The anti-icing,anti-stalling effect of alkyl pyridinium halides inmotor fuels was evaluated in a carburetor icing demonstrator apparatus consisting of a vacuum pump equipped .so that cool moisture-saturated air. from an ice tower is drawn through a simple glass tube gasoline carburetor. The gasoline sample is placed in a sample bottle and is drawn into the glass carburetor through a hypodermic needle which is 20 gauge in size. Evaporation of the gasoline in the glass tube further cools the cold moist air with resulting ice formation of the throttle plate. The formation of ice on the throttle plate causes the engine to stall and it has been found that this condition is equivalent to a pressure drop across the throttle plate of about 0.5 inch of mercury. In the test, the time to reach 0.5 inch of mercury pressure drop is recorded. The vacuum pump is adjusted to give a vacuum of 1.8 inches of mercury and the test is run until a pressure of 2.3 inches of mercury has been reached or is run for 300 seconds. Since with most fuels this pressure drop is reached in 1 to 4 minutes, 300 seconds is the maximum time for a run. A recording of 300 seconds indicates no stalling within the test period. Each fuel is run 4 times in succession and the average is recorded. If the difference between the runs are great, the glass tube carburetor and the test throttle are washed with alcohol, flushed out with gasoline and the runs repeated. A leaded winter grade premium gasoline having a Reid vapor pressure of about 13 gives a stall in amout 45-65 seconds in this test. Additives which raise the stalling time to over 200 seconds are regarded as effective anti-stalling, anti-icing additives.

The base fuel employed in Table I below to evaluate the effectiveness of lauryl pyridinium chloride was a winter grade premium gasoline having an ASTM research octane rating about 99.7 containing 2.4 cc. of TEL per gallon. This gasoline had a 50 ASTM distillation point of 234 F. and a Reid vapor pressure of 12.0 lbs.

TABLE I Carburetor icing test Lbs./ 1000 bbl. of lauryl pyridinium chloride in the gasoline: Time to stalling None 180 The octane rating of the fuel containing lauryl pyridinium chloride was also obtained in order to find out what effect the additive might have on the octane rating of the fuel. It was determined that lauryl pyridinium chloride had no adverse effect on the octane'rating. In fact, at the higher p.t.b. dosages it increased the octane rating.

The base fuel employed to evaluate the effectiveness of the cetyl pyridinium bromide and cetyl pyridinium chloride was a winter grade premium gasoline having'a research octane rating of about 98.8 and containing 1.96 cc. of TEL per gallon. This gasoline also had a 50 ASTM distillation point of 218 F. and a Reid vapor pressure of about 11.8 lbs. The anti-icing test results for these additives are given in Table II below.

TABLE II Carburetor icing test Lbs/1000 bbl. of cetyl pyridinium bromide: Time to stalling 69 4 300+ 8 300+ 16 300+ 32 300+ Lbs/1000 bbl. of cetyl pyridinium chloride:

The foregoing data conclusively demonstrates the effectiveness of alkyl pyridinium halides as anti-icing, antistalling additives for motor fuel compositions. These additives can be used in both leaded and unleaded gasolines, and are effective in conjunction with conventional motor fuel additives including lead scavenger compounds, metal deactivators, gum inhibitors, fuel line anti-icing hydroxy compounds and dyes.

I claim:

1. A gasoline having a Reid vapor pressure above 9 and containing 0.001 to 0.1 weight percent of an alkyl pyridinium halide having the formula:

in which R is an alkyl radical having from 6 to 28 carbon atoms and X is a halogen atom.

2. A gasoline in accordance with claim 1 in which said halogen atom is selected from the group consisting of chlorine, bromine and iodine.

3. A gasoline according to claim 1 in which R is an alkyl radical having from 10 to 18 carbon atoms.

-4. A gasoline having a Reid vapor pressure above 9 and containing 0.001 to 0.1 weight percent of cetyl pyridinium chloride.

5. A gasoline having a Reid vapor pressure above 9 and containing 0.001 to 0.1 weight percent of cetyl pyridinium bromide.

6. A gasoline having a Reid vapor pressure above 9 and containing 0.001 to 0.1 weight percent of lauryl pyridinium chloride.

7. A gasoline having a Reid vapor pressure above 9 and containing 0.001 to 0.02 weight percent of an alkyl pyridinium halide having the'forrnula:

in which R is an alkyl radical having from 10 to 18 carbon atoms and X is selected from the group consisting of chlorine and bromine.

References Cited by the Examiner UNITED STATES PATENTS 1,524,674 2/ 25 Sadtler 4463 2,242,224 5/41 Bley 252357 2,265,759 12/41 Lawton et a1 252-357 2,363,778 11/44 Pedersen 4463 2,919,684 1/60 Carr 4463 OTHER REFERENCES Petroleum Refining With Chemicals, Kalichevsky et. al., 2nd Edition, Elsevier Publishing Co., 1956, page 480.

Surface Active Agents, Schwartz-Perry, Interscience Publishers Inc., 1949, page 159.

DANIEL E. WYMAN, Primary Examiner. 

1. A GASOLINE HAVING A REID VAPOR PRESSURE ABOVE 9 AND CONTAINING 0.001 TO 0.1 WEIGHT PERCENT OF AN ALKYL PYRIDINIUM HALIDE HAVING THE FORMULA: 